JP3907099B2 - Optical glass - Google Patents

Description

【００４９】
【表２】

【００５０】
【表３】

【００５１】
【表４】

【００５２】
実施例４９
実施例１〜４８の各ガラスを、上述のように約１〜 ３Ｌの重量分になる程度に調合し、０．１〜５ｄＰａ・ｓの粘性になる温度（約１０００℃〜１２００℃）で原料をＳｉＯ₂ルツボ、またはＰｔ製のルツボで２〜５時間溶解し、ガラス原料をガラス化させた。こうして得られた粗ガラス（カレット）を２ＬのＰｔ製のプリフォ−ムが作成できる溶融炉に再投入し、０．１〜５ｄＰａ・ｓの粘性になる温度（約１０００℃〜１２００℃）でカレットを溶解、脱泡、清澄を２〜５時間行った。清澄でガラス内に泡が無い状態になったことを確認した後、ガラスが成形できる温度（粘性５〜３０ｄＰａ・ｓ、温度で１０００℃〜８００℃）にまで、溶融炉と流出パイプ内（パイプ上部の溶融炉に近い方は内径１５ｍｍφ、流出先端部は内径１．５ｍｍφ全長約２ｍ）を降温した。降温後、所定の粘性になった後、流出パイプより流出させてＮ₂浮上ガスを出した状態の成形型で受けた。直径０．５〜５０ｍｍの球状物または楕円球状に成形してプリフォーム（精密プレス成形用素材）を得た。得られたプリフォームは、形状、重量ともにバラツキのないものであった。
【００５３】
このプリフォームを図１に示された上型１及び下型２の間に配置した後、石英管１１内を窒素雰囲気としてヒーター１２に通電して石英管１１内を加熱した。成形型内の温度を、被成形ガラス塊の粘度が約１０⁷〜１０⁸ ｄＰａ・ｓとなる温度とした後、この温度を維持しつつ、押し棒１３を降下させて上型１を上方から押して成形型内の被成形ガラス塊をプレスした。プレスの圧力は８ＭＰａ、プレス時間は３０秒間とした。プレスの後、プレスの圧力を解除し、非球面プレス成形されたガラス成形体を上型１及び下型２と接触させたままの状態でガラス転移温度まで徐冷し、次いで室温付近まで急冷して非球面に成形されたガラスを成形型から取り出した。得られた非球面レンズは、プレス時に透明性が損なわれることもなく、極めて精度の高いレンズであった。
【００５４】
比較例１〜２２
特開平０７−９７２３４号公報の実施例に記載のガラス（比較例１〜９）、特開平０５−２７０８５３号公報の実施例に記載のガラス（比較例１０〜１１）、特開昭５２−１３２０１２号公報の実施例に記載のガラス（比較例１２〜２２）を調製し、各ガラスの屈折率(nd)、アッベ数(νd)、屈伏点(Ts)、液相温度(LT)を測定した。失透性についても観察した。結果を表５〜７に示す。
【００５５】
【表５】

【００５６】
【表６】

【００５７】
【表７】

【００５８】
特開平０７−９７２３４号公報の実施例に記載のガラス（比較例１〜９）（表５）は、屈折率が１．７３以下の実施例であり、これらは屈伏点Ｔｓが５２０℃を越える特性となるものが多い。これはＬｉ₂Ｏ含有量が０〜０．５重量％であることに起因していると推測される。また、Ｌｉ₂Ｏが０〜０．５重量％の範囲であってもＴｓが５２０℃未満の実施例もある（比較例３、５、７）が、この場合、ガラス原料として高価なＧｅＯ₂を使用している問題がある。これら実施例のガラスにおいてＧｅＯ₂をフリ−にすると（比較例４、６、８）液相温度（ＬＴ）が９００℃を越えてしまうという問題がある。
【００５９】
特開平０５−２７０８５３号公報の実施例に記載のガラス（比較例１０〜１１）（表６）は、屈折率が１．６４〜１．７３であり、いずれも液相温度が９００℃を越えている。またこれらのガラスはＴｓも５２０℃を越えている。
【００６０】
特開昭５２−１３２０１２号公報の実施例に記載のガラス（比較例１２〜２２）（表７）は、屈折率が１．６４〜１．７３であり、Ｔｓが５２０℃を越えている。また、実施例２、３（比較例１３、１４）に記載のガラスを除いてＬｉ₂Ｏをも含まれていないことが、Ｔｓが５２０℃を越える一因と考えられる。Ｌｉ₂Ｏを０．５重量％越えて含んでいる実施例２及び３（比較例１３、１４）のガラスであってもＴｓは５２０℃を越え、液相温度も９００℃を越える。
【００６１】
【発明の効果】
以上のように、本発明によれば、屈伏点および液相温度がともに低く、結晶、泡の残留、脈理、着色、変形不良が認められない光学ガラスを得ることができる。したがってこのガラスを用いることにより、比較的低温の精密プレス成形が可能になり、プレス時のプレス成形型とガラスの融着を防止することができる。またプレスマシンへの大きな熱負荷がかからないため、熱による部品の損傷の恐れも無い。
本発明の光学ガラスは、液相温度が９００℃以下と耐失透性に優れ、屈伏点が５２０℃以下と比較的低温域の加熱でプレス成形可能な特性を有しているため、成形温度を５４０℃以下にでき、かつプレス成形時のガラスの安定性にも優れる。
さらに液相温度が低いので、耐失透性に優れ、溶融ガラスより精密プレス成形用素材を成形する際や、プレス成形のための加熱などにおいてもガラスの結晶化を防止することができる。さらに、ガラス溶解時に発生する泡がガラス中に残留せず、脈理や着色や変形不良も認められない高品質な光学ガラスを得ることができる。
【図面の簡単な説明】
【図１】精密プレス成形装置の１例の概略を示す断面図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical glass having a medium-high refractive index and a high dispersion characteristic, which can be pressed at a relatively low temperature and has a relatively low yield point and liquidus temperature.
[0002]
[Prior art]
Several optical glasses having medium-high refractive index and high dispersion characteristics are known.
For example, Japanese Patent Laid-Open No. 07-97234 discloses P₂O_Five, Na₂O, Nb₂O_FiveAnd WO_ThreeA low melting point optical glass having a medium high refractive index and a high dispersion characteristic containing a predetermined amount of is described. This optical glass is described as having a refractive index of 1.69 to 1.83, a dispersion ratio of 21 to 32, and a yield point of 570 ° C. or lower. However, when the examples described in JP 07-97234 A with a refractive index of 1.73 or less are compared, many have a characteristic that the yield point Ts exceeds 520 ° C. This is Li₂It is presumed that the O content is from 0 to 0.5% by weight. Li₂There are also examples in which Ts is less than 520 ° C. even when O is in the range of 0 to 0.5% by weight (Examples 6, 7, and 8). In this case, however, GeO is expensive as a glass raw material.₂There is a problem using. In the glass of these examples, GeO₂Is free, the liquidus temperature (hereinafter sometimes referred to as “LT”) exceeds 900 ° C .. This is P₂O_FiveIs estimated to be caused by being 32% or less.
[0003]
Japanese Patent Application Laid-Open No. 05-270853 discloses SiO.₂, B₂O_Three, P₂O_Five, Nb₂O_FiveAnd Na₂O + K₂An optical glass having a medium-high refractive index and a high dispersion characteristic containing a predetermined amount of O is described. In the glass described in this publication, the liquid phase temperature of each of the glasses described in Examples having a refractive index of 1.64 to 1.73 exceeds 900 ° C. This is P₂O_FiveIt is presumed that the content is 32% by weight or less. These glasses also have Ts exceeding 520 ° C. This is Na₂It is presumed that O is 5% by weight or less.
[0004]
Japanese Patent Laid-Open No. 52-133201 discloses B₂O_Three, P₂O_FiveAnd Nb₂O_FiveAn optical glass having a medium-high refractive index and a high dispersion characteristic containing a predetermined amount of is described. All the glasses described in Examples having a refractive index described in this publication having a refractive index of 1.64 to 1.73 have Ts exceeding 520 ° C. This is Na₂It is presumed that O is 5% by weight or less. In addition, Li except for the glass described in Examples 2 and 3.₂The fact that O is not contained is also considered to be a cause of Ts exceeding 520 ° C. Li₂Even in the glasses of Examples 2 and 3 containing 0.5% by weight of O, Ts exceeds 520 ° C., and the liquidus temperature exceeds 900 ° C. This is P₂O_FiveNb at 32 wt% or less₂O_FiveIt is surmised that it is caused by containing more than 30% by weight.
[0005]
[Problems to be Solved by the Invention]
Usually, glass press molding is carried out in a temperature range approximately 20 to 60 ° C. higher than the yield point temperature Ts of glass. When the yield point temperature of glass exceeds 520 ° C, the press temperature becomes at least 540 ° C or higher. For this reason, the tendency for the glass and the molding surface of the mold to react with each other increases, which causes the life of the mold to be shortened and is not suitable for mass production.
Further, when the liquidus temperature is high, the tendency to devitrification near the softening point of the glass, that is, near the molding temperature in press molding, becomes strong.
[0006]
Furthermore, the glass preform used for the reheat press is required to have no variation in shape and weight. Therefore, when a preform is formed by hot forming, the forming is performed at a predetermined viscosity that is less likely to vary in shape and weight. For this reason, it is necessary that the glass is not easily devitrified at a temperature exhibiting a viscosity suitable for molding, that is, the liquidus temperature is lower than a temperature exhibiting a viscosity suitable for molding. From such a viewpoint, the liquidus temperature needs to be 800 to 900 ° C.
[0007]
However, most of the glasses described in the above-mentioned prior art have a refractive index in the range of 1.64 to 1.72 and an Abbe number of 29 to 36. It is a glass that exceeds 520 ° C and the liquidus temperature exceeds 900 ° C. In the glass for press molding, considering the life of the mold and the tendency to devitrify the glass, the yield point is 520 ° C. or lower, and the liquidus temperature is relatively low, and particularly preferably 900 ° C. or lower.
[0008]
Therefore, an object of the present invention is an optical glass having a medium high refractive index and a high dispersion characteristic having a yield point of 520 ° C. or lower and a liquidus temperature of relatively low, particularly 900 ° C. or lower. The object is to provide an optical glass having a range of 1.64 to 1.72 and an Abbe number of 29 to 36.
[0009]
[Means for Solving the Problems]
  The invention for achieving the above object is as follows.
[Claim 1]
Displayed in weight%, P₂O_FiveOver 32% and 45% or less, Li₂O over 0.5% and below 6%, Na₂O exceeds 5% and 22% or less, Nb₂O_Five6-30%, B₂O_Three0.5 to 10%, WO_Three0 to 35%, K₂0-14% O, Na₂O + K₂10 to 24% of O and the total of the above components is 80% or moreAnd TiO ₂ 0 to 5%Optical glass.
[Claim 2]
Displayed in weight%, the P₂O_FiveThe content is more than 32% and 40% or less, the Li₂O content is 1-4%, Na₂O content is 10-19%, said Nb₂O_FiveThe content is 10% to 28%, the B₂O_ThreeContent is 1-5%, K₂O content is 0-8%, Na₂O + K₂The optical glass according to claim 1, wherein the O content is 12 to 22%, and the total of the components is 80% or more.
[Claim 3]
Na₂O content is 12-17%, said Nb₂O_FiveContent is 15-26%, said K₂O content is 0 to 4%, Na₂O + K₂O content is 14-19%,WO _Three Content is 0-18%The optical glass according to claim 2.
[Claim 4]
Expressed in wt%, SiO₂0 to 2%, Al₂O_Three0-5%, ZnO 0-15%, BaO 0-12%, Sb₂O_Three0% or more and less than 1%, SnO₂The optical glass according to any one of claims 1 to 3, further comprising 0 to 1%, and a total of the above components and the components according to any one of claims 1 to 3 is 95% or more. .
[Claim 5]
Expressed in weight%, Al₂O₃5 to 3%, further containing 0 to 9% ZnO, and the total of the above components and the components according to any one of claims 1 to 4 is 95% by weight or more. The optical glass according to claim 1.
[Claim 6]
SiO₂The optical glass according to claim 4 or 5, wherein the content is 0 to 1%.
[Claim 7]
SiO₂Content is 0% or more and less than 0.5%, the said ZnO content is 0 to 5%, The sum total of the said component and the component of any one of Claims 1-6 is 98% or more, Item 7. The optical glass according to Item 5 or 6.
[Claim 8]
SaidWO_Three Content isThe optical glass according to any one of claims 1 to 7, which is 3 to 15%.
[Claim 9]
Displayed in weight%, Li₂O over 0.5% and below 6%, Na₂O over 5% and under 22%, K₂0-14% O, Na₂O + K₂10-24% O, Nb₂O_Five6-30%, P₂O_FiveTheOver 32%45% or lessTiO ₂ 0-5%An optical glass containing phosphate glass having a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, and a yield point (Ts) of 520 ° C. or lower.
[Claim 10]
Displayed in weight%, Li₂O over 0.5% and below 6%, Na₂O over 5% and under 22%, K₂0-14% O, Na₂O + K₂10-24% O, Nb₂O_Five6-30%,P ₂ O _Five More than 32% and 45% or less,WO_Three0-35%, Al₂O_Three0-5%, TiO₂0% or more5% or lessAn optical glass comprising a phosphate glass having a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, and a yield point (Ts) of 520 ° C. or lower.
[Claims11]
Displayed in weight%, P₂O_FiveOver 32% and 45% or less, Li₂O over 0.5% and below 6%, Na₂O exceeds 5% and 22% or less, Nb₂O_Five6-30%, B₂O_Three0.5 to 10%, WO_Three0 to 35%, K₂0-14% O, Na₂O + K₂10-24% O, SiO₂0 to 2%, Al₂O_Three0-5%, TiO₂0% or more5% or lessZnO 0-15%, BaO 0-12%, Sb₂O_Three0% or more and less than 1%, SnO₂0 to 1%, the total content of the above components is 95% or more, the refractive index (nd) is 1.64 to 1.72, the Abbe number (νd) is 29 to 36, the yield point ( An optical glass having a Ts) of 520 ° C. or lower.
[Claims12]
Displayed in weight%, P₂O_FiveOver 32% and 45% or less, Li₂O over 0.5% and below 6%, Na₂O exceeds 5% and 22% or less, Nb₂O_Five6-30%, B₂O_Three0.5-10%TiO ₂ 0-5%SiO which is contained and is an optional component₂Is a phosphate glass having a content of 2% by weight or less, a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, and a yield point (Ts) of 520 ° C. or less. An optical glass having a liquidus temperature (LT) of 900 ° C. or lower.
[Claims13]
Expressed in weight%, MgO is 0-5%, CaO is 0-5%, SrO is 0-5%, La₂O_Three0 to 3%, Y₂O_Three0 to 3%, Gd₂O_Three0 to 3%, ZrO₂0 to 3%, As₂O_Three0% or more and less than 1%, Ta₂O_Five0 to 3%, In₂O_Three0 to 3%, TeO₂0-3%, Bi₂O_Three0 to 3%, GeO₂0 to 1% further, the above components and claims 1 to12The sum of the components according to any one of claims 1 to 99 is 99% or more.12Optical glass of any one of these.
[Claims14]
Claims 1 to13An optical component comprising the optical glass according to any one of the above.
[Claims15]
It is for precision press molding.13Optical glass of any one of these.
[Claims16]
Claim15A glass preform obtained by preforming the optical glass.
[Claims17]
Claim16Glass optical component obtained by reheat press molding using a glass preform.
[Claims18]
Claims 1 to13 and 15An optical component formed by press-molding the optical glass according to any one of the above.
[0010]
Hereinafter, unless otherwise specified, the refractive index is nd and the Abbe number is νd. Ts represents the yield point and LT represents the liquidus temperature.
Unlike the glass described in JP-A-07-97234, the glass of the present invention is expensive GeO as a glass raw material.₂However, Ts is 520 ° C. or less, and the press temperature can be lowered. Further, the glass of the present invention has a glass liquid phase temperature of 900 ° C. or lower, and does not cause striae, volatile adhesion, or shape defects when the preform in the pre-press molding stage is hot-formed. Can be.
Further, the glass of the present invention is different from the glass described in Japanese Patent Application Laid-Open No. 05-270853.₂O_FiveThe liquidus temperature was made 900 ° C. or less by containing more than 32%. Therefore, it is possible to mold so as not to cause striae, adherence of volatile matter, and shape failure when the preform before press molding is hot molded. Furthermore, the glass of the present invention comprises Na₂Since O is contained exceeding 5% by weight, Ts is 520 ° C. or less, and it is not necessary to increase the press temperature of the press machine, and there is an advantage that no heat load is applied to the press machine.
Further, the glass of the present invention is different from the glass described in JP-A No. 52-133201, and Na₂Containing O in excess of 5% by weight, Li₂Contains O in excess of 0.5% by weight, P₂O_FiveMore than 32% by weight, Nb₂O_FiveWas 30% by weight or less. As a result, it became suitable for glass for precision presses having a Ts of 520 ° C. or lower and a liquidus temperature of 900 ° C. or lower.
[0011]
In the present specification, “%” means wt% unless otherwise specified.
Oxides are represented by typical chemical symbols, and are included even when the oxidation-reduction state of Ti, Nb, W, Sb, Sn, Zr, As, Ta, In, Te, Ge, etc. fluctuates. To do. Specifically, for example, a part of Ti is reduced to form TiO._1.9Including TiO₂Is written.
Below, the reason for limitation of each component in the glass of this invention, especially the glass of Claims 1-8 is demonstrated.
P₂O_FiveIs a glass forming component. In the glass of the present invention, in order to obtain a yield point of 520 ° C. or less and good devitrification resistance, phosphate glass is preferable, and P₂O_FiveIs more preferably 45% by weight or less of phosphate glass, P₂O_FiveEven more preferable is a phosphate glass having a content of 32 wt% or more and 45 wt% or less. P₂O_FiveIf the content exceeds 45% by weight, it becomes difficult to obtain a target refractive index (1.64 or more). Considering the case of nd> 1.66 and chemical durability, P₂O_FiveThe content is preferably more than 32% by weight and not more than 40% by weight.
[0012]
Li₂O is a component having an effect of lowering Ts. Li₂If the O content is 0.5% by weight or less, the desired characteristics of Ts ≦ 520 ° C. cannot be obtained. Li₂If the O content exceeds 6% by weight, the desired liquidus temperature of 900 ° C. or less cannot be obtained. Li₂When the O content is in the range of 1 to 4% by weight, Ts ≦ 510 ° C. and the liquidus temperature ≦ 860 ° C., which is more preferable in production.
[0013]
Na₂O is a component having an effect of lowering Ts. Na₂If the O content is 5% by weight or less, the desired characteristics of Ts ≦ 520 ° C. cannot be obtained. Na₂When the O content exceeds 22% by weight, the chemical durability deteriorates. Na₂When the O content is in the range of 10 to 19% by weight, chemical durability is good, and a glass having a liquidus temperature of 860 ° C. or lower with Ts ≦ 510 ° C. or lower is preferable. In addition, Na₂When the O content is in the range of 12 to 17% by weight, chemical durability is good, and a glass having a liquidus temperature of 840 ° C. or lower with Ts ≦ 510 ° C. or lower is more preferable.
[0014]
Nb₂O_FiveIs a component capable of imparting the characteristics of nd ≧ 1.64 and νd ≦ 36 to the glass. Nb₂O_FiveIf the content is less than 6% by weight, the desired refractive index (nd ≧ 1.64) and dispersion characteristics (νd ≦ 36) cannot be obtained. Nb₂O_FiveIf the content exceeds 30% by weight, the liquidus temperature exceeds 900 ° C. Nb₂O_FiveThe content is preferably 10% to 28% by weight. In this range, nd ≧ 1.66, the liquidus temperature ≦ 860 ° C., and Ts ≦ 510 ° C. Nb₂O_FiveThe content is more preferably in the range of 15% by weight to 26% by weight. In this range, nd ≧ 1.66 and the liquidus temperature ≦ 840 ° C.
[0015]
B₂O_ThreeIs P₂O_FiveIt is a component that assists the glass-forming component and lowers the liquidus temperature. B₂O_ThreeIf the content is less than 0.5% by weight, the liquidus temperature exceeds 900 ° C. B₂O_ThreeIf the content exceeds 10% by weight, Ts> 520 ° C. is reached. B₂O_ThreeThe content is preferably 1% by weight to 5% by weight. In this range, Ts ≦ 510 ° C. and the liquidus temperature ≦ 860 ° C.
[0016]
WO_ThreeIs an optional component, but by adding an appropriate amount in an amount of 35% by weight or less, while maintaining the characteristics of Ts ≦ 520, liquidus temperature (hereinafter referred to as “LT”) ≦ 900 ° C., nd is 1. 64 to 1.72 and νd can be easily adjusted within the range of 36 to 29. WO_ThreeWhen the content exceeds 35% by weight, coloring becomes strong. WO_ThreeThe content is preferably in the range of 0 to 18% by weight. In this range, it is difficult to color and nd and νd are easily adjusted in the range of nd1.65 to 1.71 and νd35.5 to 30 while maintaining the characteristics of Ts ≦ 510 ° C and LT ≦ 860 ° C. Can do. WO_ThreeThe content is more preferably in the range of 3 to 15% by weight. In this range, nd and νd can be easily adjusted in the range of nd1.66 to 1.70 and νd35 to 30 while maintaining the characteristics of Ts ≦ 510 ° C. and LT ≦ 840 ° C.
[0017]
K₂O is an optional component, but nd within the range of nd1.64 to 1.72 and νd36 to 29 while maintaining the characteristics of Ts ≦ 520 and LT ≦ 900 ° C. by adding an appropriate amount of 14% by weight or less. νd can be easily adjusted. K₂When the O content exceeds 14% by weight, the chemical durability deteriorates. K₂The O content is preferably 0 to 8% by weight. In this range, chemical durability is good, and nd and νd are easy in the range of nd1.65 to 1.71 and νd35.5 to 30 while maintaining the characteristics of Ts ≦ 510 ° C and LT ≦ 860 ° C. Can be adjusted. K₂The O content is more preferably in the range of 0 to 4% by weight. In this range, nd and νd can be easily adjusted in the range of nd1.66 to 1.70 and νd35 to 30 while maintaining the characteristics of Ts ≦ 510 ° C. and LT ≦ 840 ° C.
[0018]
Na₂O + K₂O is a component having an effect of lowering Ts. Na₂O + K₂If the O content is less than 10% by weight, the desired characteristics of Ts ≦ 520 ° C. cannot be obtained. Na₂O + K₂If the O content exceeds 24% by weight, the chemical durability deteriorates. Na₂O + K₂When the O content is in the range of 12 to 22% by weight, the chemical durability is good, and a glass having a liquidus temperature of 860 ° C. or less with Ts ≦ 510 ° C. is obtained. In particular, Na₂O + K₂When the O content is in the range of 14 to 19% by weight, the chemical durability is good, and a glass having a liquidus temperature of 840 ° C. or lower and Ts ≦ 510 ° C. is obtained.
[0019]
SiO₂Can be easily adjusted in the range of nd1.65 to 1.71 and νd35.5 to 30 by adding an appropriate amount of an optional component in an amount of 2% by weight or less. SiO₂If the content exceeds 2% by weight, Ts may exceed 520 ° C. Considering glass coloring, SiO₂When it is melted with a crucible, an amount of 0 to less than 0.5% may be mixed in the glass. Therefore, SiO₂The content is preferably 0 to less than 0.5% by weight. In the optical glass according to claim 7, SiO 2₂The content is preferably 0 to 0.4% by weight or less.
[0020]
Al₂O_ThreeIs an optional component, and when it is added in an appropriate amount of 5% by weight or less, the chemical durability of the glass is improved. However, if it exceeds 5% by weight, the solubility when the glass raw material is melted deteriorates, and the melting temperature rises. As a result, when it dissolves with a Pt crucible, the amount of Pt mixed increases, and problems such as deterioration of coloring tend to occur. Even when dissolved with a Si crucible, SiO₂As a result, the Ts exceeds 520 ° C. Al₂O_ThreeThe content is preferably in the range of 0 to 3% by weight.
[0021]
TiO₂Is an optional component. When an appropriate amount is added in an amount of less than 8% by weight, the chemical durability of the glass is improved, nd can be increased, and νd can be highly dispersed. However, TiO₂When 8% by weight or more is added, coloring tends to deteriorate. TiO₂The content is preferably 0 to 6% by weight, more preferably 0 to 5% by weight. The optical glass of claim 7, wherein TiO₂More preferably, the content is 0 to 4.9% by weight.
[0022]
ZnO is an optional component. When an appropriate amount is added in an amount of 15% by weight or less, the chemical durability of the glass is improved, and Ts is reduced. However, if it exceeds 15% by weight, νd> 36 may be obtained. The ZnO content is preferably 0 to 9% by weight, more preferably 0 to 5% by weight.
[0023]
BaO is an optional component. When an appropriate amount is added in an amount of 12% by weight or less, the adjustment of nd and νd becomes easy in the range of nd1.65-1.71 and νd35.5-30. However, if it exceeds 12% by weight, LT exceeds 900 ° C., which is not preferable. The BaO content is preferably 0 to 6% by weight.
[0024]
Sb₂O_Three, As₂O_ThreeIs an optional component, and when added in an appropriate amount, it has a defoaming and refining action of the glass. Nb₂O_FiveTiO₂, WO_ThreeIt has the effect of suppressing reductive coloring such as. However, Sb₂O_ThreeIs added by 1% by weight or more, Sb₂O_ThreeColoring by itself becomes stronger. So Sb₂O_ThreeThe content is suitably in the range of 0 to less than 1% by weight. Also, As₂O_ThreeIf 1% by weight or more is added, As₂O_ThreeColoring by itself becomes stronger. So As₂O_ThreeThe content of is suitably in the range of 0 to less than 1% by weight.
[0025]
SnO₂Is an optional component, and when an appropriate amount is added in an amount of 1% by weight or less, there is a defoaming and refining action of the glass. Nb₂O_FiveTiO₂, WO_ThreeIt has the effect of suppressing reductive coloring such as. However, SnO₂Is added over 1 wt% SnO₂Coloring by itself becomes stronger. So SnO₂The content is suitably in the range of 0 to 1% by weight.
[0026]
When an appropriate amount of MgO, CaO, and SrO is added as an arbitrary component, the adjustment of nd and νd is facilitated within the range of nd1.65 to 1.71 νd35.5 to 30. However, it is not preferable to add more than 5% by weight because LT exceeds 900 ° C. The contents of MgO, CaO, and SrO are each preferably 0 to 3% by weight.
[0027]
La₂O_Three, Y₂O_Three, Gd₂O_Three, ZrO₂, Ta₂O_Five, In₂O_Three, TeO₂, Bi₂O_ThreeIs an optional component, and when added in an appropriate amount, nd and νd can be easily adjusted in the range of nd1.65 to 1.71 and νd35.5 to 30. However, if both are added exceeding 3% by weight, LT exceeds 900 ° C. The content of these components is preferably 0 to 1% by weight.
[0028]
The optical glass of the present invention preferably does not contain PbO in consideration of safety. GeO₂Is not included because it is expensive, or even if it is included, it is preferably in the range of 0 to 1% by weight.
[0029]
In the glass according to claim 1 and 2, the total of the components described in each claim is 80% or more, which is in the range of refractive index 1.64 to 1.72, Abbe number 29 to 36, This is because the liquid phase temperature is preferably 900 ° C. or lower and the yield point is preferably 520 ° C. or lower.
Further, in the glasses according to claims 4 and 5, the sum of the components according to each claim is 95% or more, and this is a range of a refractive index of 1.64 to 1.72 and an Abbe number of 29 to 36. This is because it is preferable to provide a glass having a liquidus temperature of 900 ° C. or lower, a yield point of 520 ° C. or lower, and having no coloring or chemical durability in practical use.
[0030]
In addition, the liquid phase temperature (LT) of the optical glass of the present invention is usually 900 ° C. or lower, but the content of each component is adjusted so that it is preferably 860 ° C. or lower, more preferably 840 ° C. or lower. Is desirable. On the other hand, the yield point (Ts) is usually 520 ° C. or lower, but it is desirable to adjust the content of each component so that it is preferably 510 ° C. or lower.
[0031]
  Li in the phosphate glass of claim 9₂O, Na₂O, K₂O, Na₂O + K₂O, Nb₂O_FiveThe reason for limiting the content of each component is the same as that of the glass of the first to eighth aspects. P₂O_FiveThe reason for containing 45% or less is the same as that of the glass of claims 1-8. Furthermore, in the phosphate glass according to claim 9, the refractive index is 1.64 to 1.72, the Abbe number is 29 to 36, and the yield point is 520 ° C. or lower. From the viewpoint of an optical glass, it is suitable to be an optical glass having medium refractive index and high dispersion characteristics having the above refractive index and Abbe number. Also, glass for press moldingPerspectiveTherefore, considering the life of the mold and the tendency to devitrify the glass, the yield point is 520 ° C. or less. The optical glass having such a refractive index, Abbe number, and yield point can be appropriately obtained from a glass containing the components described in claim 9 within the scope described in claim 9. Also in the glass according to claim 9, B₂O_ThreeContaining 0.5 to 10% by weight is preferable, TiO₂Those containing 0 to 4.9% by weight are also preferred.
[0032]
  Li in the phosphate glass according to claim 10.₂O, Na₂O, K₂O, Na₂O + K₂O, Nb₂O_Five, WO_Three, Al₂O_ThreeTiO₂The reason for limiting the content of each component is the same as that of the glass of the first to eighth aspects. Further, the refractive index is 1.64 to 1.72, the Abbe number is 29 to 36, and the yield point is 520 ° C. or lower. From the viewpoint of an optical glass, it is suitable to be an optical glass having medium refractive index and high dispersion characteristics having the above refractive index and Abbe number. Also, glass for press moldingPerspectiveTherefore, considering the life of the mold and the tendency to devitrify the glass, the yield point is 520 ° C. or less. The optical glass having such a refractive index, Abbe number, and yield point can be appropriately obtained from a glass containing the components described in claim 10 in the range described in claim 10.
[0033]
  In the glass according to claim 9 and 10, P₂O_FiveContent is more than 32% and less than 45%TheThe reason is P in the invention of claim 1.₂O_FiveThis is the same as the reason for limiting the content.
[0034]
  Claim11P in the glass described in₂O_Five, Li₂O, Na₂O, Nb₂O_Five, B₂O_Three, WO_Three, K₂O, Na₂O + K₂O, SiO₂, Al₂O_ThreeTiO₂, ZnO, BaO, WO_Three, Sb₂O_Three, SnO₂The reasons for limiting the content of each component are the same as those of the glasses of the first to eighth aspects. Further, the refractive index is 1.64 to 1.72, the Abbe number is 29 to 36, and the yield point is 520 ° C. or lower. From the viewpoint of an optical glass, it is suitable to be an optical glass having medium refractive index and high dispersion characteristics having the above refractive index and Abbe number. Also, glass for press moldingPerspectiveTherefore, considering the life of the mold and the tendency to devitrify the glass, the yield point is 520 ° C. or less. The optical glass having such a refractive index, Abbe number, and yield point can be appropriately obtained from a glass containing the components described in claim 12 in the range described in claim 12. Furthermore, the total content of the above components is 95% or more. This is because the liquidus temperature is 900 ° C. or lower and the yield point is in the range of refractive index 1.64 to 1.72 and Abbe number 29 to 36. This is because it is preferable for obtaining characteristics of 520 ° C. or lower.
[0035]
  Further claims12-13The reason for limitation of each component in the glass as described in 1 is the same as the reason for limitation of each component in the optical glass according to claim 1. And claims13In the glass described in (1), the total of the components described in each claim is 99% or more. This is because the liquidus temperature is 900 in the range of the refractive index of 1.64 to 1.72 and the Abbe number of 29 to 36. This is because it is preferable in order to obtain the characteristics of ℃ or lower and yield point of 520 ℃ or lower. In addition, as an optical glass of Claims 1-13, P is used.₂O_Five, Li₂O, Na₂O, Nb₂O_Five, B₂O_Three, WO_Three, Al₂O_ThreeTiO₂, ZnO, Sb₂O_ThreeThe total content of is more preferably 95% by weight or more, more preferably 99% by weight or more, and particularly preferably 100% by weight.
[0036]
Such an optical glass of the present invention can be produced by preparing a raw material compound by a conventional method and dissolving, clarifying, stirring, and homogenizing.
The present invention also provides a precision press-molding material comprising the optical glass of the present invention, an optical component comprising the optical glass, and an optical component obtained by precision press-molding the precision press-molding material. It is.
The precision press-molding material of the present invention is made of the optical glass of the present invention.
[0037]
Here, the precision press molding means press molding in which an optical functional surface is formed by press molding, and the precision press molding material means a glass material to be molded used at the time of precision press molding.
As an example of precision press-molding, first, melted, stirred, clarified, and homogenized molten glass with a viscosity of about 1000 ° C. to 1200 ° C. of about 0.1 to 5 dPa · s is discharged from an outflow pipe to form a mold ( In general, it is different from the press mold), and a precision press molding material called a preform such as a sphere or an ellipsoid is produced, and the preform is reheated and pressure-molded with the upper mold and the lower mold. . At this time, in view of the shape of the molded product and the like, a body mold can be used as appropriate.
As a preform, it can be formed by cold forming or hot glass forming from molten glass, and further by mirror polishing or the like.
[0038]
As a method of hot forming, there is a method of dropping or flowing molten glass from an outflow pipe and receiving it with a receiving mold through a gas and then forming it into a desired shape, for example, a spherical shape or a flat spherical shape. .
In the case of dropping, the viscosity of the molten glass of 0.1 to 5 dPa · s is adjusted to a dropable viscosity, and a spherical or elliptical spherical preform is obtained by dropping the molten glass. The dropped glass may be solidified during dropping, or may be floated on the gas to be ejected and solidified while being rotated.
Moreover, when making it flow down, the viscosity of 0.1-5 dPa * s molten glass is adjusted to the viscosity suitable for flow down, this is made to flow down from an outflow pipe, glass is cut | disconnected, and this glass to flow down through gas After receiving with a receiving mold, the glass is formed into a sphere or a flat sphere and solidified. The glass that has flowed down at this time is preferably cut without using a cutting blade. For example, such glass can be cut by lowering the receiving mold after receiving it with a receiving mold.
[0039]
Thus, when shape | molding the glass dripping or flowing down to a preform, it is preferable that it is 5 dPa * s or more as a viscosity of the glass dripping or flowing down from a pipe. The viscosity of the dropped glass is more preferably 3 to 30 dPa · s, and the viscosity of the flowing glass is more preferably 5 to 60 dPa · s.
At this time, in order to make the molten glass of 0.1 to 5 dPa · s have a viscosity of 5 dPa · s or more, the temperature in the pipe of the molten glass outflow pipe is set to 1000 ° C. to 800 ° C. The temperature is lowered to 900 ° C to 800 ° C. At this time, in the conventional optical glass having a liquidus temperature exceeding 900 ° C., the preform is crystallized unless the pipe tip temperature is set to a temperature exceeding 900 ° C. and the viscosity is extremely low. Therefore, even if it is received in the mold, it may cause deformation failure and striae failure.
[0040]
In contrast, the optical glass of the present invention has a low liquidus temperature of usually 900 ° C. or lower, and maintains a stable glass state even at a viscosity suitable for preform molding. There is no crystallization even when hot forming, and no striae or deformation defects occur.
[0041]
[Isothermal press]
FIG. 1 is a cross-sectional view schematically showing an example of a precision press molding apparatus. In the apparatus shown in FIG. 1, a heater 12 is wound around an outer periphery of a support base 10 provided on a support bar 9 on which a molding die including an upper die 1, a lower die 2 and a guide die 3 is placed. This is provided in the quartz tube 11. The molded glass preform 4 made of the medium high refractive index / high dispersion optical glass of the present invention can be, for example, a sphere or an oval sphere having a diameter of about 0.5 to 50 mm. The size of the sphere or oval sphere is appropriately determined in consideration of the size of the final product.
After the glass preform 4 to be molded is placed between the lower mold 2 and the upper mold 1, the heater 12 is energized to heat the inside of the quartz tube 11. The temperature in the mold is controlled by a thermocouple 14 inserted in the lower mold 2. The heating temperature is such that the viscosity of the glass preform 4 to be molded is suitable for precision press, for example, about 10⁷-10⁸ The temperature is about dPa · s. After reaching a predetermined temperature, the push rod 13 is lowered and the upper mold 1 is pushed from above to press the glass preform 4 to be molded in the mold. The press pressure and time can be appropriately determined in consideration of the viscosity of the glass. For example, the pressure can be in the range of about 5 to 15 MPa, and the time can be 10 to 300 seconds. After the pressing, the optical component of the present invention can be obtained by gradually cooling to the glass transition temperature, then rapidly cooling to room temperature, and taking out the molded product from the mold.
[0042]
[Non-isothermal press]
The optical glass of the present invention can also be applied to a press molding method in which a glass preform and a mold are press molded under the following temperature conditions.
A glass preform has a viscosity of 10⁹ It is softened by heating to a temperature corresponding to less than dPa · s. The viscosity of the glass preform is 10⁹ By being less than dPa · s, 10⁹ The glass material can be sufficiently deformed and molded with a mold preheated to a temperature corresponding to a viscosity of dPa · s or higher. In order to mold the mold at a relatively low temperature, the glass material is preferably 10^5.5 -10^7.6 It is appropriate to soften by heating to a temperature corresponding to dPa · s. The preheating temperature of the mold is such that the viscosity of the glass material is 10⁹ -10¹²The temperature is equivalent to dPa · s. Viscosity is 10¹²If the temperature is lower than the temperature corresponding to dPa · s, it may be difficult to obtain a glass molded product having a thin edge by greatly stretching the glass material. On the other hand, the viscosity is 10⁹ If the temperature exceeds the temperature corresponding to dPa · s, the molding cycle time becomes longer than necessary, and the life of the mold is shortened.
[0043]
[Direct press]
It is also possible to perform direct pressing from a molten glass lump without using a preform. In this case, since the liquidus temperature is as low as 900 ° C. or less, the molten glass flows down from the outflow pipe without crystallizing the glass. There is an advantage that the allowable range when selecting the temperature condition for pressing and the temperature condition for pressing can be widened.
[0044]
[Normal press forming]
The optical glass of the present invention can be applied not only to precision press molding, but also to press molding methods for grinding and polishing. Specifically, it is as follows.
When optical components are made directly from agitation and homogenized molten glass, the agitated and homogenized molten glass is supplied from the outflow pipe onto the lower mold surface of the press mold. This glass is pressure-molded by an opposing upper mold and lower mold (referred to as direct press). The obtained molded product is ground and polished as necessary to become an optical component.
Also, the homogenized molten glass can be cooled once, cold worked into the desired shape, reheated, and pressure-molded with a molding die. Accordingly, it is ground and polished to become an optical component.
Furthermore, optical components can be produced by grinding and polishing glass.
[0045]
In each of the above molding methods, the shape of the upper mold, the lower mold, or the barrel mold is appropriately selected, and various lenses such as a spherical lens, an aspheric lens, a microlens, a lens array, and a microlens array, a prism, and a polygon Optical parts such as mirrors can be molded.
[0046]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the physical property of optical glass was measured by the method shown below.
(1) Refractive index (nd) and Abbe number (νd)
It measured about the optical glass obtained by making slow cooling temperature-fall rate into -30 degrees C / h.
(2) Sag temperature (Ts)
Using a thermal expansion measuring device, the measurement was performed under the condition of a temperature rising rate of 8 ° C./min.
(3) Liquidus temperature (LT)
It hold | maintained for 30 minutes in the devitrification test furnace with the temperature gradient of 400-1050 degreeC, the presence or absence of the crystal | crystallization was observed with the microscope of 100 time magnification, and the liquidus temperature was measured. Further, the devitrification property near the softening point (press temperature) was also visually observed at the time of measuring the liquidus temperature.
[0047]
Examples 1-48
According to the glass composition shown to Tables 1-4, the optical glass of Examples 1-48 was prepared by the conventional method. That is, as a raw material, P₂O_FiveFor the other components, phosphate compounds such as diphosphorus pentoxide, orthophosphoric acid, metaphosphate, etc., and for other components, carbonates, nitrates, hydroxides, oxides, etc. are used, and these raw materials are weighed to a desired ratio. Example 1 was prepared by mixing and mixing to prepare a raw material for preparation, which was put into a melting furnace heated to 1000 ° C. to 1200 ° C., dissolved, clarified, stirred, homogenized, cast into a mold, and gradually cooled. -48 optical glasses were obtained.
The composition of the obtained optical glass has a fluctuation much smaller than plus or minus 1% with respect to the glass compositions shown in Tables 1 to 4, and therefore can be said to be almost the same as the glass compositions shown in Tables 1 to 4. It was a thing.
As is apparent from the table, each of the glasses of Examples 1 to 48 has a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, and a yield point (Ts). Was 520 ° C. or lower. The liquidus temperature (LT) was all 900 ° C. or lower. Neither undissolved material, devitrification, residual foam, striae, or coloring was observed in the glass of each example.
As can be seen from these results, the glass of each example was suitable for press molding, particularly precision press molding.
[0048]
[Table 1]

[0049]
[Table 2]

[0050]
[Table 3]

[0051]
[Table 4]

[0052]
Example 49
Each glass of Examples 1 to 48 is prepared to a weight of about 1 to 3 L as described above, and the raw material is used at a temperature (about 1000 ° C. to 1200 ° C.) at which the viscosity becomes 0.1 to 5 dPa · s. SiO₂It melt | dissolved for 2 to 5 hours with the crucible or the crucible made from Pt, and the glass raw material was vitrified. The crude glass (cullet) thus obtained was re-introduced into a melting furnace capable of producing a 2 L Pt preform, and the cullet was heated to a viscosity of 0.1 to 5 dPa · s (about 1000 ° C. to 1200 ° C.). Was dissolved, defoamed and clarified for 2 to 5 hours. After confirming that the glass is clear and free of bubbles, it is melted in the melting furnace and the outflow pipe (pipe) to a temperature at which the glass can be molded (viscosity 5 to 30 dPa · s, temperature 1000 ° C. to 800 ° C.). The temperature close to the upper melting furnace was an inner diameter of 15 mmφ and the outflow tip was an inner diameter of 1.5 mmφ and a total length of about 2 m). After lowering the temperature, after having reached a predetermined viscosity, let it flow out from the outflow pipe.₂The mold was received with the floating gas released. A preform (precision press-molding material) was obtained by molding into a spherical product or an elliptical sphere having a diameter of 0.5 to 50 mm. The obtained preform had no variation in shape and weight.
[0053]
After this preform was placed between the upper die 1 and the lower die 2 shown in FIG. 1, the quartz tube 11 was heated by energizing the heater 12 with the inside of the quartz tube 11 being a nitrogen atmosphere. The temperature inside the mold is adjusted so that the viscosity of the glass block to be molded is about 10⁷-10⁸ After setting the temperature to be dPa · s, while maintaining this temperature, the push rod 13 was lowered and the upper mold 1 was pushed from above to press the glass molding in the mold. The press pressure was 8 MPa, and the press time was 30 seconds. After pressing, the pressure of the press is released, and the glass molded body formed by aspherical press is gradually cooled to the glass transition temperature while being in contact with the upper die 1 and the lower die 2, and then rapidly cooled to near room temperature. The glass formed into an aspherical surface was taken out of the mold. The obtained aspherical lens was a highly accurate lens without losing transparency during pressing.
[0054]
Comparative Examples 1-22
Glass described in Examples of JP-A-07-97234 (Comparative Examples 1 to 9), Glass described in Examples of JP-A-05-270853 (Comparative Examples 10 to 11), JP-A 52-13320 Glasses (Comparative Examples 12 to 22) described in Examples of No. 1 were prepared, and the refractive index (nd), Abbe number (νd), yield point (Ts), and liquidus temperature (LT) of each glass were measured. . Devitrification was also observed. The results are shown in Tables 5-7.
[0055]
[Table 5]

[0056]
[Table 6]

[0057]
[Table 7]

[0058]
Glasses (Comparative Examples 1 to 9) (Table 5) described in Examples of Japanese Patent Application Laid-Open No. 07-97234 are Examples having a refractive index of 1.73 or less, and these have a yield point Ts exceeding 520 ° C. There are many characteristics. This is Li₂It is presumed that the O content is from 0 to 0.5% by weight. Li₂There is an example in which Ts is less than 520 ° C. even if O is in the range of 0 to 0.5 wt% (Comparative Examples 3, 5, and 7). In this case, GeO is expensive as a glass raw material.₂There is a problem using. In the glass of these examples, GeO₂Is made free (Comparative Examples 4, 6, 8), there is a problem that the liquidus temperature (LT) exceeds 900 ° C.
[0059]
Glasses (Comparative Examples 10 to 11) (Table 6) described in Examples of JP-A No. 05-270853 have a refractive index of 1.64 to 1.73, and the liquid phase temperature exceeds 900 ° C. in all cases. ing. These glasses also have Ts exceeding 520 ° C.
[0060]
Glasses (Comparative Examples 12 to 22) (Table 7) described in Examples of JP-A No. 52-133201 have a refractive index of 1.64 to 1.73, and Ts exceeds 520 ° C. Further, Li except for the glasses described in Examples 2 and 3 (Comparative Examples 13 and 14).₂The fact that O is not contained is also considered to be a cause that Ts exceeds 520 ° C. Li₂Even in the glasses of Examples 2 and 3 (Comparative Examples 13 and 14) containing O in an amount exceeding 0.5 wt%, Ts exceeds 520 ° C. and the liquidus temperature exceeds 900 ° C.
[0061]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain an optical glass in which both the yield point and the liquidus temperature are low, and no crystals, bubbles remain, striae, coloring, or deformation defects are not recognized. Therefore, by using this glass, it becomes possible to perform precision press molding at a relatively low temperature, and to prevent fusion between the press mold and the glass at the time of pressing. In addition, since there is no large heat load on the press machine, there is no risk of damage to the parts due to heat.
The optical glass of the present invention is excellent in devitrification resistance with a liquidus temperature of 900 ° C. or lower, and has a yield point of 520 ° C. or lower and has a characteristic that can be press-molded by heating in a relatively low temperature range. Can be made 540 ° C. or lower, and the stability of the glass during press molding is excellent.
Further, since the liquidus temperature is low, the glass is excellent in devitrification resistance, and crystallization of the glass can be prevented even when a precision press-molding material is formed from molten glass or in heating for press molding. Furthermore, it is possible to obtain a high-quality optical glass in which bubbles generated during melting of the glass do not remain in the glass and no striae, coloring, or deformation defects are observed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an outline of an example of a precision press molding apparatus.

Claims (18)

Expressed in weight%, P ₂ O ₅ is more than 32% and 45% or less, Li ₂ O is more than 0.5% and less than 6%, Na ₂ O is more than 5% and less than 22%, Nb ₂ O ₅ the 6 to 30% B ₂ O ₃ and 0.5 to 10% WO ₃ and 0 to 35% K ₂ O and 0 to 14%, a Na ₂ O + K ₂ O containing 10 to 24%, and the Ri der total 80 percent or more of the ingredients, optical glass containing further TiO ₂ 0 to 5%. Expressed in weight%, the P ₂ O ₅ content is more than 32% and 40% or less, the Li ₂ O content is 1 to 4%, the Na ₂ O content is 10 to 19%, the Nb ₂ The O ₅ content is 10% to 28%, the B ₂ O ₃ content is 1 to 5%, the K ₂ O content is 0 to 8%, and the Na ₂ O + K ₂ O content is 12 to 22%. The optical glass according to claim 1, wherein the total amount of the components is 80% or more. The Na ₂ O content is 12 to 17%, the Nb ₂ O ₅ content is 15 to 26%, the K ₂ O content is 0 to 4%, and the Na ₂ O + K ₂ O content is 14 to 19%. The optical glass according to claim 2, wherein the WO ₃ content is 0 to 18% . Expressed in weight percent, SiO ₂ is 0-2%, Al ₂ O ₃ is 0-5%, ZnO is 0-15%, BaO is 0-12%, Sb ₂ O ₃ is 0% or more and less than 1%. the SnO ₂ containing further 0 to 1%, and the components and according to any one of claims 1 to 3 the sum of the components described is 95% or more to any one of claims 1 to 3 Optical glass. Expressed in weight%, Al ₂ O ₃ is further contained in an amount of 0 to 3%, ZnO is further contained in an amount of 0 to 9%. % Or more of the optical glass according to claim 1. The optical glass according to claim 4, wherein the SiO ₂ content is 0 to 1%. The SiO ₂ content is 0% or more and less than 0.5%, the ZnO content is 0 to 5%, and the total of the above components and the components according to any one of claims 1 to 6 is 98% or more. The optical glass according to claim 5 or 6. The optical glass according to claim 1, wherein the content of WO ₃ is ₃ to 15%. Expressed in weight%, Li ₂ O exceeds 0.5% and 6% or less, Na ₂ O exceeds 5% and 22% or less, K ₂ O ranges from 0 to 14%, and Na ₂ O + K ₂ O ranges from 10 to 10%. A phosphate glass containing 24%, Nb ₂ O ₅ of 6 to 30%, P ₂ O ₅ of more than 32% to 45% or less and TiO ₂ of 0 to 5% , having a refractive index (nd) of 1 Optical glass having .64 to 1.72, Abbe number (νd) of 29 to 36, and yield point (Ts) of 520 ° C. or lower. Expressed in weight%, Li ₂ O exceeds 0.5% and 6% or less, Na ₂ O exceeds 5% and 22% or less, K ₂ O ranges from 0 to 14%, and Na ₂ O + K ₂ O ranges from 10 to 10%. 24%, Nb ₂ O ₅ 6-30%, P ₂ O ₅ more than 32% and 45% or less, WO ₃ 0-35%, Al ₂ O ₃ 0-5%, TiO ₂ 0% or more An optical glass having a phosphate glass containing 5% or less , a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, and a yield point (Ts) of 520 ° C. or less. . Expressed in weight%, P ₂ O ₅ is more than 32% and 45% or less, Li ₂ O is more than 0.5% and less than 6%, Na ₂ O is more than 5% and less than 22%, Nb ₂ O ₅ 6-30%, B ₂ O ₃ 0.5-10%, WO ₃ 0-35%, K ₂ O 0-14%, Na ₂ O + K ₂ O 10-24%, SiO ₂ 0 to 2%, the Al ₂ O ₃ 0 to 5%, of TiO ₂ less than 5% 0% the ZnO 0 to 15%, 0 to 12% of BaO, and Sb ₂ O ₃ less than 1% 0% or more, It contains 0 to 1% of SnO ₂ , the total content of the above components is 95% or more, the refractive index (nd) is 1.64 to 1.72, the Abbe number (νd) is 29 to 36, An optical glass having a point (Ts) of 520 ° C. or lower. Expressed in weight%, P ₂ O ₅ is more than 32% and 45% or less, Li ₂ O is more than 0.5% and less than 6%, Na ₂ O is more than 5% and less than 22%, Nb ₂ O ₅ 6 to 30%, B ₂ O ₃ 0.5 to 10% , TiO ₂ 0 to 5% , and the content of SiO ₂ as an optional component is 2% by weight or less. An optical glass having a refractive index (nd) of 1.64 to 1.72, an Abbe number (νd) of 29 to 36, a yield point (Ts) of 520 ° C. or lower, and a liquidus temperature (LT) of 900 ° C. or lower. . In% by weight, the MgO 0 to 5%, the CaO 0 to 5%, 0 to 5% of SrO, La ₂ O ₃ and 0 to 3%, Y ₂ O ₃ and 0 to 3%, Gd ₂ 0 to 3% for O ₃ , 0 to 3% for ZrO ₂ , 0% to less than 1% for As ₂ O ₃ , 0 to 3% for Ta ₂ O ₅ , 0 to 3% for In ₂ O ₃ , TeO ₂ 0 to 3%, Bi ₂ O ₃ to 0 to 3%, GeO ₂ to 0 to 1%, and the total of the above components and the components according to any one of claims 1 to 12 is 99% or more. The optical glass according to any one of claims 1 to 12 . Optical components made of optical glass according to any one of claims 1 to 13. The optical glass according to any one of claims 1 to 13 , which is used for precision press molding. A glass preform obtained by preforming the optical glass of claim 15 . A glass optical component obtained by reheat press molding using the glass preform of claim 16 . The optical component formed by press-molding the optical glass of any one of Claims 1-13 and 15 .

Images